Reasons for performing study: Diagnosis of osteochondrosis (OC) is based on clinical signs and radiography, but alternative methods for detection at an early stage would be useful.
Objectives: To determine in the juvenile horse the relationship between serum concentrations of a number of biomarkers that reflect changes in cartilage and bone turnover and age, feeding level, growth, and the occurrence of OC.
Method: Foals were assigned to a high (n = 20) or moderate (n = 19) feeding level group from birth to age one year. Bodyweight, withers height and cannon width were measured. Osteoarticular status was assessed radiographically at 5.5 and 11 months in all foals, and by necropsy at 12 months for 8 foals/group. Serum biomarkers of bone (osteocalcin, CTX-1) and cartilage (CPII, C2C) metabolism were assayed at 8 time points between ages 2 and 52 weeks. Ratios between biomarkers of tissue formation and degradation were calculated at each time point.
Results: Consistent age-related patterns in biomarker serum concentrates were found, indicating a markedly higher metabolism before age 20 weeks but concentrations were not affected by feeding level. Bodyweight was correlated negatively to C2C and CTX-1, and withers height was positively correlated to osteocalcin and the osteocalcin/CTX-1 and CPII/C2C ratios. Osteocalcin concentration at 2 weeks and CPII/C2C ratio at 20 weeks had strong positive correlations to OC, as diagnosed radiographically at 5.5 months. Osteocalcin had a strong correlation with radiographically detected OC at 11 months but at that time there was no significant relationship between CPII/C2C ratio and OC.
Conclusions: Occurrence of OC lesions is significantly associated with anabolic changes in bone metabolism during the first weeks post partum, given the strong relation with osteocalcin.
Potential relevance: Measuring osteocalcin concentrations during the first few weeks post partum may have potential value for the prediction of risk for OC development.